Bypass PS on MK4

Happy Holidays, Bob!From your ST-70 reply below, would an MK4 with 80,40,30,20 PS cap benefit from bypassing, too? These amps have the VTA boards. Where's the best place to add these bypass caps?Also, whats the best way to wire the PS cap, the same as stock, 80 to the choke, 40 and 30 soldered together and to B+? Thanks,Gordy

Pooch wrote:Happy Holidays, Bob!From your ST-70 reply below, would an MK4 with 80,40,30,20 PS cap benefit from bypassing, too? These amps have the VTA boards. Where's the best place to add these bypass caps?Also, whats the best way to wire the PS cap, the same as stock, 80 to the choke, 40 and 30 soldered together and to B+? Thanks,Gordy

Hi Gordy,

The bypass capacitors are really only useful if you add a large capacitors (100 uF or higher) to the quad cap. If you do add a large capacitor, add it to the 80 section which powers the output transformer on your Mark 4. The larger the capacitor you add - the more the need of bypass capacitors. If you do add a bypass capacitor or bank of bypass capacitors add them to either the 80 section or the 20 section which are wired together with a jumper when you use the VTA driver board on a Mark 4.

If you just use the 80, 40, 30, 20 cap as it is without any additional capacitance then you don't need any bypass capacitors.